Computation time on a random ChemDB [29] background data set consisting of about 175,000 compounds. This includes reading, typing, and generation of the feature map objects. Empirical computation time was obtained on a dual core AMD Opteron(tm) Processor 280, 2.4 GHz, 2 GByte RAM, Java Runtime Environment 1.6, Linux kernel 2.6.18, using a single core.